In the washing of fabrics and other substrates, such as dishware, it is known to use bleaching agents to remove different types of stains. The bleaching agents may be combined with the detergent chemistries, such as being already combined in the detergent liquid or powder sold to the appliance user. In such situations, the bleaching agent is incorporated into the wash liquor at the same time as other cleaning chemistries, such as enzymes, and the two types of chemistries may counteract or lessen the effectiveness of the other, thereby reducing the potential cleaning ability of the detergent.
Further, bleaching agents may not be stable over long periods of time, particularly if the bleaching agent is in an active state or condition. This then either requires that the bleaching agent be provided in a stable, but inactive condition, in which it is less effective in providing a bleaching or oxidizing action, or requires that the bleaching agent be used promptly after its formulation, reducing the effective shelf life of the detergent.
It is known to activate bleaching agents with metal ions which catalyze an activation reaction to produce an active bleaching agent. The use of these ions in a wash system, however, could potentially cause environmental concerns if allowed to pass into the waste water system.
When the inactive bleaching agent and the metal ions are provided simultaneously with the detergent, such as by being provided in a power form so that the bleaching agent remains stable, the user loses control over when the bleaching action occurs during the wash cycle, and is unable to selectively activate the bleaching agent when desired in the wash cycle.